10 Food ChainThe relationship between plants and animals that shows who eats what. Energy is transferred from one organism to another through the food chain
11 Food WebA model of feeding relationships, describing the connections among all food chains within an ecosystem
12 Energy PyramidA representation of the loss of useful energy at each step in a food chain
13 Pyramid of NumbersBased on the number of organisms needed to make a simple food chain. Shows how large populations of certain organisms are needed to support very small populations of other organisms.
14 SymbiosisAn interactive association between two or more species living together; may be parasitic, commensal, or mutualistic. The relationship between two organisms
15 CommensalismA symbiotic relationship in which one species benefits and the other is not affected
16 ParasitismA form of symbiosis in which the population of one species benefits at the expense of the population of another species
17 MutualismA symbiotic interaction between two species in which both derive some benefit
18 CompetitionOne of the biological interactions that can limit population growth; occurs when two species vie with each other for the same resource
19 PopulationAll the organisms that belong to the same species living in a community
20 CommunityAll the populations of different species that live in an ecosystem
21 HabitatPlace where an organism lives and that provides the types of food, shelter, moisture, and temperature needed for survival
22 NicheAn organism’s place in the ecosystem: where it lives, what it consumes, what consumes it, and how it interacts with all biotic and abiotic factors. A unique ecological role of an organism in a community.